The invention relates to a method for the wireless transmission of data between at least one communication unit, which is arranged in or on a rotatable part and to which at least one sensor (S) and/or actuator is respectively connected, and at least one base communication unit which is arranged in radio reception range outside of the rotating part.
The invention also relates to a rotatable part having at least one communication unit for the wireless transmission of data between the at least one communication unit and at least one base communication unit which is arranged in radio reception range outside of the rotating part.
In rotor telemetry, sensors capture measurement data for physical parameters, such as pressure, temperature or vibration, on predominantly rotating parts. These parameters are emitted in the form of data in a transmission signal by means of special communication units which are mounted in or on the rotatable part and which are provided with moving antennas, and are received and evaluated by static antennas on at least one base communication unit which are arranged in radio reception range at the perimeter of the rotatable part. Owing to rising demands on transmission systems with rotor telemetry in terms of greater flexibility and a higher data rate, the transmitters and receivers are increasingly being implemented in digital form.
The known digital radio-assisted systems in rotor telemetry are based on narrowband, low-rate single-carrier methods, which have a limited data rate for a frequency channel.
One such telemetry module for a rotating part is known from EP 1 843 011 A2, for example.
Claus W. Kupferschmidt: Modellierung zyklisch stationärer Kanäle für die funkgestützte Rotortelemetrie [Modeling of cyclically steady channels for radio-assisted rotor telemetry], Hannoversche Beiträge zur Nachrichtentechnik, 1st edition, 09/2007, Shaker-Verlag publishers, describes the conventional methods for data transmission which are used for rotor telemetry, all of which use modulation onto a radio-frequency carrier. When a central radio-frequency carrier of this kind is used, a high data rate in the transmitter results in a reduced symbol duration. The effects of multipath propagation become ever more problematic when symbols are shortened. If the dispersion of the radio channel is in the order of magnitude of the symbol duration or distinctly above it, the transmission quality is disrupted by heavy symbol interference. This sometimes requires complex signal equalization.
In this case, the datastreams can be transmitted using a plurality of low-rate radio-frequency carriers, as a result of which the symbol duration per carrier can be significantly greater than the dispersion of the radio channel. Although this counteracts heavy symbol interference, a multi-radio-frequency-carrier solution of this kind involves a proportional increase in the circuit complexity for the rotor-based communication units as the number of different radio-frequency carriers used increases.